Travertine is part of the limestone family and is very popular flooring in Cornwall and the South West. It is formed in hot springs called Karst and is generally tan or beige in colour but can have reds and silver running through it. The characteristic holes you see in the stone are formed by water movement. The holes are often filled by coloured Portland cement or coloured resins. Travertine comes in a three types of finish polished, tumbled or honed. Polished travertine can look blotchy where the fillers used do not take to the polish. Travertine needs regular maintenance involving sealing or impregnating as the the stone is extremely acid sensitive.